On 13/06/2019 20:03, Stephen Suryaputra wrote:
> Multipath hash policy value of 0 isn't distributing since the outer IP
> dest and src aren't varied eventhough the inner ones are. Since the flow
> is on the inner ones in the case of tunneled traffic, hashing on them is
> desired.
>
> This is done mainly for IP over GRE, hence only tested for that. But
> anything else supported by flow dissection should work.
>
> v2: Use skb_flow_dissect_flow_keys() directly so that other tunneling
> can be supported through flow dissection (per Nikolay Aleksandrov).
> Signed-off-by: Stephen Suryaputra <ssuryae...@gmail.com>
> ---
> Documentation/networking/ip-sysctl.txt | 1 +
> net/ipv4/route.c | 20 ++++++++++++++++++++
> net/ipv4/sysctl_net_ipv4.c | 2 +-
> 3 files changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/networking/ip-sysctl.txt
> b/Documentation/networking/ip-sysctl.txt
> index 5eedc6941ce5..2f3bc910895a 100644
> --- a/Documentation/networking/ip-sysctl.txt
> +++ b/Documentation/networking/ip-sysctl.txt
> @@ -80,6 +80,7 @@ fib_multipath_hash_policy - INTEGER
> Possible values:
> 0 - Layer 3
> 1 - Layer 4
> + 2 - Inner Layer 3 for tunneled IP packets.
Hmm, but you're using the ports below, so it's not L3 ?
>
> fib_sync_mem - UNSIGNED INTEGER
> Amount of dirty memory from fib entries that can be backlogged before
> diff --git a/net/ipv4/route.c b/net/ipv4/route.c
> index 14c7fdacaa72..c3e03bce0a3a 100644
> --- a/net/ipv4/route.c
> +++ b/net/ipv4/route.c
> @@ -1872,6 +1872,26 @@ int fib_multipath_hash(const struct net *net, const
> struct flowi4 *fl4,
> hash_keys.basic.ip_proto = fl4->flowi4_proto;
> }
> break;
> + case 2:
> + memset(&hash_keys, 0, sizeof(hash_keys));
> + hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
> + /* skb is currently provided only when forwarding */
> + if (skb) {
> + struct flow_keys keys;
> +
> + skb_flow_dissect_flow_keys(skb, &keys, 0);
> +
> + hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
> + hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
> + hash_keys.ports.src = keys.ports.src;
> + hash_keys.ports.dst = keys.ports.dst;
> + hash_keys.basic.ip_proto = keys.basic.ip_proto;
This is inconsistent with the code below, you're using ports when we have skb
and
using only addresses when we don't (host traffic). So either make it L3-only and
use addresses or make sure you're using the correct ports as well.
> + } else {
> + /* Same as case 0 */
> + hash_keys.addrs.v4addrs.src = fl4->saddr;
> + hash_keys.addrs.v4addrs.dst = fl4->daddr;
> + }
> + break;
> }
> mhash = flow_hash_from_keys(&hash_keys);
>
> diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
> index 2316c08e9591..e1efc2e62d21 100644
> --- a/net/ipv4/sysctl_net_ipv4.c
> +++ b/net/ipv4/sysctl_net_ipv4.c
> @@ -960,7 +960,7 @@ static struct ctl_table ipv4_net_table[] = {
> .mode = 0644,
> .proc_handler = proc_fib_multipath_hash_policy,
> .extra1 = &zero,
> - .extra2 = &one,
> + .extra2 = &two,
> },
> #endif
> {
>
